diff --git a/qutebrowser/utils/urlutils.py b/qutebrowser/utils/urlutils.py
index 35ef07d8a..2406ed43a 100644
--- a/qutebrowser/utils/urlutils.py
+++ b/qutebrowser/utils/urlutils.py
@@ -468,6 +468,28 @@ class IncDecError(Exception):
         return '{}: {}'.format(self.msg, self.url.toString())
 
 
+def _get_incdec_value(match, incdec, url):
+    """Get a incremented/decremented URL based on a URL match."""
+    pre, zeroes, number, post = match.groups()
+    # This should always succeed because we match \d+
+    val = int(number)
+    if incdec == 'decrement':
+        if val <= 0:
+            raise IncDecError("Can't decrement {}!".format(val), url)
+        val -= 1
+    elif incdec == 'increment':
+        val += 1
+    else:
+        raise ValueError("Invalid value {} for indec!".format(incdec))
+    if zeroes:
+        if len(number) < len(str(val)):
+            zeroes = zeroes[1:]
+        elif len(number) > len(str(val)):
+            zeroes += '0'
+
+    return ''.join([pre, zeroes, str(val), post])
+
+
 def incdec_number(url, incdec, segments=None):
     """Find a number in the url and increment or decrement it.
 
@@ -513,26 +535,7 @@ def incdec_number(url, incdec, segments=None):
         if not match:
             continue
 
-        pre, zeroes, number, post = match.groups()
-        # This should always succeed because we match \d+
-        val = int(number)
-        if incdec == 'decrement':
-            if val <= 0:
-                raise IncDecError("Can't decrement {}!".format(val), url)
-            val -= 1
-        elif incdec == 'increment':
-            val += 1
-        else:
-            raise ValueError("Invalid value {} for indec!".format(incdec))
-        if zeroes:
-            if len(number) < len(str(val)):
-                zeroes = zeroes[1:]
-            elif len(number) > len(str(val)):
-                zeroes += '0'
-
-        new_value = ''.join([pre, zeroes, str(val), post])
-        setter(new_value)
-
+        setter(_get_incdec_value(match, incdec, url))
         return url
 
     raise IncDecError("No number found in URL!", url)
diff --git a/tests/unit/utils/test_urlutils.py b/tests/unit/utils/test_urlutils.py
index dfd591449..707edd704 100644
--- a/tests/unit/utils/test_urlutils.py
+++ b/tests/unit/utils/test_urlutils.py
@@ -600,8 +600,7 @@ class TestIncDecNumber:
         url = 'http://example.com/{}'
         base_url = QUrl(url.format(number))
         expected_url = QUrl(url.format(expected))
-        new_url = urlutils.incdec_number(
-                base_url, incdec, segments={'path'})
+        new_url = urlutils.incdec_number(base_url, incdec, segments={'path'})
         assert new_url == expected_url
 
     @pytest.mark.parametrize('url, segments, expected', [